Wai-San Chang (also known as Mr. Chang) is the boss of a branch of the Triads based in Thailand. Like Revy, he is adept with wielding a pistol in each hand (Beretta 76 and AMT Hardballer) in a fashion similar to that of gun fu. Chang is far more proficient in it than Revy (in episode 11 she actually confesses that she is "not on his level yet," an unprecedented admission of anything less than perfection on her own part; it remains unclear, however, whether or not she is referring to gunplay in general or Chang's own particular style), and it is implied that it is he who taught her this style of combat. It may be this prowess in combat that makes Chang the only male to whom Revy respectfully refers to as "Sir".

Mr. Chang is based on characters commonly played by Chow Yun Fat in films by John Woo, such as John Lee in Replacement Killers and especially Mark Gor in A Better Tomorrow, as both Chang and Gor are members of the Hong Kong Triad, wield dual pistols and don similar attire.

Unlike most criminal bosses in the town, he advocates cooperation and joint ventures.